from math import sqrt

class  Point (object):
    def __init__(self, x, y):
        self.x = x
        self.y = y

def d (p1, p2):
    return sqrt((p1.x - p2.x) ** 2 + (p1.y - p2.y) ** 2)

data = [float(e) for e in input().split()]
p1 = Point(data[0], data[1])
p2 = Point(data[2], data[3])

print(d(p1, p2)) from math import sqrt class  Point (object):
    def __init__(self, x, y):
        self.x = x
        self.y = y Point def __init__(self, x, y):
        self.x = x
        self.y = y __init__ self.x = x self.x self x x self.y = y self.y self y y self self x x y y object def d (p1, p2):
    return sqrt((p1.x - p2.x) ** 2 + (p1.y - p2.y) ** 2) d return sqrt((p1.x - p2.x) ** 2 + (p1.y - p2.y) ** 2) sqrt((p1.x - p2.x) ** 2 + (p1.y - p2.y) ** 2) sqrt (p1.x - p2.x) ** 2 + (p1.y - p2.y) ** 2 (p1.x - p2.x) ** 2 p1.x - p2.x p1.x p1 x p2.x p2 x 2 (p1.y - p2.y) ** 2 p1.y - p2.y p1.y p1 y p2.y p2 y 2 p1 p1 p2 p2 float(e) for e in input().split() for e in input().split() e input().split() ().split () input split for e in input().split() float(e) float e data = [float(e) for e in input().split()] data [float(e) for e in input().split()] p1 = Point(data[0], data[1]) p1 Point(data[0], data[1]) Point data[0] data 0 data[1] data 1 p2 = Point(data[2], data[3]) p2 Point(data[2], data[3]) Point data[2] data 2 data[3] data 3 print(d(p1, p2)) print d(p1, p2) d p1 p2 def d (p1, p2):
    return sqrt((p1.x - p2.x) ** 2 + (p1.y - p2.y) ** 2) def d (p1, p2):
    return sqrt((p1.x - p2.x) ** 2 + (p1.y - p2.y) ** 2) d class  Point (object):
    def __init__(self, x, y):
        self.x = x
        self.y = y class  Point (object):
    def __init__(self, x, y):
        self.x = x
        self.y = y Point data = [float(e) for e in input().split()] [float(e) for e in input().split()] data p2 = Point(data[2], data[3]) Point(data[2], data[3]) p2 p1 = Point(data[0], data[1]) Point(data[0], data[1]) p1
from math import sqrt

class  Point (object):
    def __init__(self, x, y):
        self.x = x
        self.y = y

def d (p1, p2):
    return sqrt((p1.x - p2.x) ** 2 + (p1.y - p2.y) ** 2)

data = [float(e) for e in input().split()]
p1 = Point(data[0], data[1])
p2 = Point(data[2], data[3])

print(d(p1, p2))
